Not a statement

Question

I am learning from a book to code with java. It gives an example of a guessing game and gives the code. I wanted to keep it as a reference. But I keep getting an error. And it might be the way I typed it cause I am reading it off a kindle and it kinda got a little messed up.

There are many errors like this, but none like mine. I am trying to make a guessing game, but I keep getting this error:

GuessingGame.java:17: not a statement (int)(Math.random() * 10) + 1;

Code:

import java.util.Scanner;
public class GuessingGame
{
    static Scanner sc = new
Scanner(System.in);
    public static void
main(String[] args)
    {
    bolean keepPlaying = true;
    System.out.println("Let's play a guessing game!");
    while (keepplaying)
    {
        bolean validInput;
        int number, guess;
        String answer;
        // Pick a random number = 
    (int)(Math.random() * 10) + 1;
        // Get the guess
        System.out.print("What do you think it is? ");
        do
        {
            guess = sc.nextInt();
            validInput = true;
            if ((guess < 1) || (guess > 10))
            {
                System.out.print
                    ("I said between 1 and 10. "
                    + "Try again: ");
                validInput = false;
            }
        }while (!validInput);
        // Check the guess
        if (guess == number)
            System.out.println(
        "You're right!");
        else
            System.out.println(
        "You're wrong! " + "The number was " + number);
        // Play again?
        do
        {
            System.out.println("\nPlay again? (Yes or No)");
            answer = sc.next();
            validInput = true;
            if (asnwer.equalsIgnoreCase("Yes"));
            else if (answer.egualsIgnoreCase("No")-
                keepPlaying = false);
            else
                        validInput = false;
        } while (!validInput);
    }
    System.out.println("\nThank you for playing!");
}

}

Answer 1

It's true, (int)(Math.random() * 10) + 1; isn't a statement. And Java, unlike some other langauges, doesn't allow just expressions as statements.

I think the word number in the comment above belongs on the line:

Not:

// Pick a random number = 
(int)(Math.random() * 10) + 1;

But:

// Pick a random number
number = (int)(Math.random() * 10) + 1;

(There's already an int number; above, so the variable is already declared and everything.)

Answer 2

You need to assign the value you are computing in the statement to a variable. IN your case it is the variable number.

number = (int)(Math.random() * 10) + 1;